scholarly journals PiROB: Vision-based pipe-climbing robot for spray-pipe inspection in nuclear plants

2018 ◽  
Vol 15 (6) ◽  
pp. 172988141881797
Author(s):  
Jae-Hee Kim ◽  
Jae-Cheol Lee ◽  
You-Rack Choi
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Mobile Robot ◽  
Nuclear Power ◽  
Climbing Robot ◽  
Pipe Inspection ◽  
Nuclear Plants ◽  
Reactor Building ◽  
Fail Safe ◽  
Very High

Among many pipes in a nuclear power plant, the spray pipes in the reactor building are one of the most important pipes in view of their function and safety aspects. However, it is very difficult to manually reach and inspect the pipes for defects or damage, because these pipes are installed in very high places. To carry out this kind of inspection more easily, we developed a mobile robot to climb up and down and to cross over such pipes. A mobile robot should be small and light enough that it can be practically and safely operated in a nuclear power plant. Our robot is able to overcome obstacles such as valves, pipe flanges, and T-shaped branches, and it also meets the requirements of fail-safe, autonomous grasping, and self-power without the cables to the remote control station. The robot has a five-degree-of-freedom manipulator and two grippers and moves along the cylindrical pipes bypassing the obstacles. The robot should be able to grasp the next pipe autonomously, because the robot works in places high off the ground where the remote operator cannot see the next pipe for the robot to grasp. This article proposes a vision-based scheme for grasping a cylindrical pipe semi-autonomously and describes its solution along with the forward kinematics and inverse kinematics of the mobile robot. The configuration of the pipe-climbing robot, including its hardware and software, is described, and the robot control with visual grasping is explained. The robot can be used practically for spray-pipe inspection as well as many potential other applications, such as inspection of the roof frame of a stadium consisting of pipes.

Monitoring of the Recovery Process of the Fukushima Daiichi Nuclear Power Plant from VHR SAR Images

2016 ◽  
Vol 11 (2) ◽  
pp. 236-245 ◽  
Author(s):  
Wen Liu ◽  
◽  
Fumio Yamazaki ◽  
Tadashi Sasagawa ◽  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Recovery Process ◽  
Sar Images ◽  
Reactor Building ◽  
Building Footprint ◽  
Intensity Images ◽  
Fukushima Daiichi ◽  
Very High

The Mw9.0 earthquake hitting the Tohoku area on Japan's Pacific coast on March 11, 2011, triggered huge tsunamis and a Fukushima Daiichi nuclear power plant breakdown. Due to high radiation levels, plant damage could only be assessed from satellite images. Our study involves four very-high-resolution (VHR) TerraSAR-X/TanDEX-X SAR intensity images taken under different acquisition conditions and used to try and determine reactor building damage. Layover and radar shadow areas were specified first based on building footprint and height, then backscattering patterns in these areas were modeled by introducing sectional views of the target building. Criteria for detecting damage from individual SAR scenes were used to compare simulated backscattering patterns to actual SAR intensity images. Damage to other reactor buildings was then identified based on these criteria. Results were confirmed by comparisons to two optical VHR WorldView-2 images and ground photos.

Decoupling Criteria for Multi-Connected Equipment

1998 ◽  
Vol 120 (1) ◽  
pp. 93-98 ◽  
Author(s):  
G. R. Reddy ◽  
H. S. Kushwaha ◽  
S. C. Mahajan ◽  
K. Suzuki
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Internal Structure ◽  
Heavy Water ◽  
Nuclear Power ◽  
Seismic Analysis ◽  
Real Life ◽  
Water Reactor ◽  
Reactor Building ◽  
Heavy Water Reactor

Generally, for the seismic analysis of nuclear power plant structures, requirement of coupling equipment is checked by applying USNRC decoupling criteria. This criteria is developed for the equipment connected to the structure at one location. In this paper, limitations of this criteria and modifications required for application to real life structures such as pressurized heavy water reactor building are discussed. In addition, the authors endeavor to present a decoupling model for multi-connected structure-equipment. The applicability of the model is demonstrated with pressurized heavy water reactor building internal structure and steam generator.

SERB Devices for the Isolation of Buildings and Equipment Against Shocks, Vibrations and Seismic Movements

2008 ◽  
Author(s):  
Viorel Serban ◽  
Adrian Panait ◽  
Marian Androne
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Horizontal Plane ◽  
Nuclear Power ◽  
Dynamic Loads ◽  
Static Loads ◽  
Maintenance And Repair ◽  
Compression Load ◽  
Aging Phenomenon ◽  
Very High

The paper presents new types of devices to isolate buildings and equipment against shocks, vibrations and seismic movements, developed by SITON in cooperation with other units in Romania. The new devices, called SERB devices, can overtake very large static loads (over 3000KN) over which dynamic loads are overlapping and damped. The devices allow the “cutting-off” of the dynamic action coming from the environment to the isolated component (building or equipment) and the shocks and vibrations generated by the component to the environment. The relative displacements allowed by the devices in horizontal plane, reach up to ±200mm and their capacity to dissipate the energy is very high. The devices can overtake compression and tension loads up to half of the maximum compression load. The devices are made of materials that practically, are not affected by the aging phenomenon and they may be guaranteed for the entire service-life of a nuclear power plant, without maintenance and repair. The sizes of the devices are small if compared with the sizes of the existing devices and the performances are similar. The radiation resistance capacity is very good allowing thus their use in all the areas of a nuclear-power plant.

Advanced Construction Technologies for the Ohma Nuclear Power Plant Reactor Building of Electric Power Development Co., Ltd.

2010 ◽  
Author(s):  
Tatsuya Obata ◽  
Akihito Urashima ◽  
Kiyokatsu Watanabe ◽  
Tsumoru Miyahara
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Electric Power ◽  
Nuclear Power ◽  
Large Scale ◽  
Construction Method ◽  
Strong Wind ◽  
Power Development ◽  
Reactor Building ◽  
Aomori Prefecture

Electric Power Development Co., Ltd has been constructing Ohma Nuclear Power Plant aiming to start commercial operation in Nov. 2014. Ohma Nuclear Power Plant is located in Ohma-town, Aomori Prefecture and is a landmark power plant in which Mixed Oxide fuels can be loaded in the full core of the reactor. Hitachi-GE Nuclear Energy Ltd. and Kajima JV, both have extensive experience of nuclear power plant construction, are the main contractors of this project and supply the entire engineering, manufacturing of all major components, and execute the construction and commissioning for the reactor building. Ohma-town is located at the northernmost part of Aomori Prefecture bordering Tsugaru strait, where is exposed to severe cold and constant strong wind in winter. Such severe weather conditions make the construction very hard, however, Hitachi and KAJIMA tries to complete the project on schedule and on budget applying highly reliable advanced construction technologies, such as open-top and parallel construction method, all whether construction method, and large scale modularization technology. The groundbreaking (acquisition of the first construction permission) was already completed in May 2008. Its civil work steadily progressed, and the rock inspection was completed in Oct. 2009. Base mat will be completed in July 2010, and both building work and mechanical work go into full swing after installation of RCCV lower liner module.

Localization Prototype Research of RCC-M Ejector in Nuclear Power Plant

2013 ◽  
Vol 421 ◽  
pp. 181-185
Author(s):  
Yan Li Qi ◽  
Yuan Xue ◽  
Tian Tian ◽  
Xing Jiang Chen ◽  
Xi Quan Fang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Stable Operation ◽  
Special Configuration ◽  
Safety Level ◽  
Practical Applications ◽  
Spray System ◽  
Nuclear Plants ◽  
Test Result

As the key equipment to ensure the stable operation of containment spray system in nuclear power plant, a RCC-M ejector with safe and credible performance is very important to make sure the containment integrality under lose of coolant accident (LOCA) or pipe broken. However, it was purchased from overseas supplier all along because of its special configuration, nonstandard design, severe safety level and small quantity demand. To implement equipment localization, and referring to practical applications of some nuclear plants, a RCC-M ejector is independently manufactured and tested, all performance could meet the requirement according to the test result. The RCC-M ejector is authenticated by experts by China Nuclear Energy Association, and the localization prototype research of this paper has great application and popularization value.

Reanalysis of the floor response spectra of the Ignalina Nuclear Power Plant Reactor Building

2017 ◽  
Vol 324 ◽  
pp. 260-268
Author(s):  
Gintautas Dundulis ◽  
Rimantas Kačianauskas ◽  
Darius Markauskas ◽  
Eugeniuš Stupak ◽  
Stanislav Stupak ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Response Spectra ◽  
Floor Response Spectra ◽  
Reactor Building ◽  
Plant Reactor

Very high temperature behaviour of a typical concrete from a nuclear power plant

2005 ◽  
Vol 90 (9) ◽  
pp. 117-124
Author(s):  
Sophie Malaval ◽  
Chistophe Journeau ◽  
Agnès Smith ◽  
Jean-Pierre Bonnet
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Temperature Behaviour ◽  
Very High

Development of Three-Dimensional Seismic Isolation Technology for Next Generation Nuclear Power Plant Applications

2005 ◽  
Author(s):  
K. Takahashi ◽  
K. Inoue ◽  
M. Morishita ◽  
T. Fujita
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
Scale Model ◽  
Isolation System ◽  
The Real ◽  
Reactor Building

Seismic isolation technology plays an important role in the area of architect engineering, especially in Japan where earthquake comes so often. This technology also makes the nuclear power plant rationalized. The horizontal base isolation with laminated rubber bearings has already been proven its effectiveness. These days, seismic isolation technology is expected to mitigate even the vertical load, which affects the structural design of primary components. Seismic isolation system has possibility to improve the economical situation for the nuclear power plant. From these points of view, a research project has been proceeded to realize practical three dimensional seismic isolation systems from 2000 to 2005 under the sponsorship of the Ministry of Economy, Trade and Industry of the Japanese government. The isolation system is developed for the supposed “Fast Breeder Reactor (abbreviated FBR)” of the next generation. Two types of seismic isolation systems are developed in the R&D project. One is a three-dimensional base isolation for a reactor building (abbreviated 3D SIS) and the other is a vertical isolation for main components with horizontal base isolation of the reactor building (abbreviated V. +2D SIS). At first step of the R&D, requirements and targets of development for the seismic isolation system were identified. Seismic condition for R&D was discussed based on the real seismic response. Vertical natural frequency and damping ratio required to the system were introduced from the response to the seismic movement. As for 3D SIS, several system concepts were proposed to satisfy the requirements and targets. Through discussions and tests on performance, reliability, applicability, maintainability, “Rolling seal type air spring system with hydraulic anti-rocking devices” was decided to be developed. Verification shaking tests with the 1/7 scale model of the system and analysis for applicability to the real plant are conducted. The result shows that the system is able to support the reactor building, to suppress the rocking motion and to mitigate the vertical seismic load. As for V.+2D SIS, coned disk spring device was selected at the beginning of R&D. Performance tests of the elements, which include common deck movement, were conducted and the system applicability to the plant is confirmed. Verification tests were conducted with 1/8 scale model of the system and the result proves the applicability to the real plant.

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